Report to the U.S. Forest Service
Xerces Society Surveys for Polites mardon mardon
in The Naches Ranger District of Washington (Summer 2007)
Polites mardon mardon photograph by Vince Harke
Sarina Jepsen, Senior Conservation Associate
Scott Hoffman Black, Executive Director
Logan Lauvray, Program Assistant
September 2007
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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TABLE OF CONTENTS
Introduction……………………………………………………………………………. 2
Survey protocol…………….………………………………………………………….. 3
Management recommendations……………………………………………………….. 4
Sites visited…………….……………………………………………………………… 8
Literature Cited……………….………………………...……………………………... 33
Acknowledgements…………………………………………...……………………….. 34
Appendix A: Table of all sites surveyed……......…….……………………………….. 35
Appendix B: Table of new Mardon skipper sites discovered in 2007………………… 36
Appendix C: Maps of all sites surveyed…………......………………………………... 37
INTRODUCTION
The Mardon skipper (Polites mardon) is a small, tawny-orange butterfly (20-24 mm)
with a stout body. The Mardon skipper is visually distinguishable from other similar
skippers by a diagnostic pattern of rectangular white spots visible on the ventral hind
wings (Pyle 2002). Mardon skippers are currently found at four geographically disjunct
areas including low elevation grasslands of coastal northern California (note: In 2007 one
Mardon skipper was found in southern Oregon approximately 20 miles northwest of
known sites in California), prairies of the South Puget Sound in Washington State, and
grasslands between roughly 500 and 1700 meters in the Cascade Mountain Range of
Washington (around Mt. Adams), and Oregon (east of Ashland). Most sites are relatively
small, and support populations of less than 50 individuals. However, there are a few
robust sites that maintain populations of over two hundred individuals. The Mardon
skipper is listed as a federal candidate species under the U.S. Endangered Species Act,
and is listed as endangered in the state of Washington (Black & Vaughan 2005).
P. mardon use more than one graminoid species for oviposition. The most common
oviposition plants in Oregon are Danthonia californica, Festuca rubra, and Carex
species. In Washington, the most common oviposition plants are Festuca idahoensis and
Carex species (Beyer & Black 2007). Oviposition studies have not been conducted in
California, but Festuca idahoensis is abundant at the known California Mardon skipper
sites (Haggard 2003). In addition, Polites mardon seem to use a variety of nectar flower
species. The most common observations were on Vicia species (Washington sites) and
Potentilla diversifolia (Oregon sites).
Most habitats are subject to a variety of anthropogenic disturbances such as recreation,
grazing, introduction of noxious weeds, various insecticides including Btk1 as well as
natural succession (i.e., conifer encroachment on meadows) which may threaten
persistence of individual sites. Little genetic exchange between populations may
contribute to possible inbreeding. Mardon skippers are assumed to have limited dispersal
(Runquist 2004), though long term studies are necessary to determine the effects of
climatic and other variables on dispersal and annual reproductive success. Lack of
genetic interchange and migration / dispersal between populations may make it
impossible for an extirpated population to become reestablished.
1
Bacillus thuringiensis var kurstaki is a lepidopteran-specific insecticide
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Taxonomy
The Mardon skipper (Polites mardon) is in the family Hesperiidae (skippers) and the
subfamily Hesperiinae (grass skippers). It was first described by W. H. Edwards (1881)
from specimens taken near Tenino, Thurston County, Washington by H. K. Morrison
(Dornfeld 1980). Mattoon et al. (1998) proposed that the Oregon population be given
subspecies status Polites mardon klamathensis and that the Washington and California
populations be considered Polites mardon mardon. Adults of P. m. klamathensis have a
consistently tawnier dorsal and ventral coloration, when compared to adults from other
populations (Warren 2005). A group of P. mardon populations exists in coastal Del Norte
County approximately 80 air miles to the west of P. m. klamathensis populations.
However the series of P. mardon from Del Norte County populations have not yet been
carefully compared to series of P. mardon mardon from Washington and the use of the
name P. mardon mardon for California populations should be considered tentative
(Warren 2005).
Summary of 2007 survey efforts
To locate new populations of Mardon skippers in Washington, Sarina Jepsen and Logan
Lauvray searched 41 sites in 14 areas over 6 days in late June and early July of 2007. All
sites are in Yakima County, except ‘Mosquito Valley 3’, which is in Lewis County. We
found 8 new populations of Mardon skippers and verified three other populations that had
been found earlier by individuals from the US Forest Service, the Washington
Department of Fish and Wildlife, and the US Fish and Wildlife Service. At one of the
sites that we revisited (Conrad Meadows), we counted the largest known Polites mardon
population (457 individuals were observed in a one day count; this site is referred to in
the report as ‘Conrad Finger 2’). In this report, we provide a summary of all sites visited,
the findings at each site, and recommendations for which sites should be revisited in
future years. We also provide general habitat management recommendations regarding
grazing, fire, conifer encroachment, use of Btk and off-road vehicle use. Appendix A lists
the geographic location of each site surveyed, and a summary of whether or not Mardon
skippers were found, and whether or not the site should be resurveyed. Appendix B
summarizes the new Mardon skipper sites discovered in 2007 as part of the Xerces
Society survey effort. Appendix C includes topographical maps of each site.
SURVEY PROTOCOL
Unless otherwise stated, all sites were surveyed during the following environmental
conditions:
Minimum temperature: Above 60 degrees Fahrenheit.
Cloud cover: Partly sunny or better. On cooler days, the sun can play a very
important role in getting butterflies to take to the air. On warmer days (above 60
degrees F), direct sunlight is less important, but a significant amount of the sun’s
energy should be coming through the clouds to help elevate the temperature of
basking butterflies.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Wind: Less than 10 MPH. On windy days, butterflies will drop out of the air if they
cannot maintain their direction and/or speed of flight.
Time of year: All sites were visited between June 27 and July 10, 2007.
We followed this protocol after arriving at each potential site:
1. Approach the site and scan for any butterfly activity, as well as suitable habitat.
2. Fill out all of the site information on datasheet.
3. Give closer attention to wetter areas first. Mardon skippers seem to prefer habitat
close to small streams or other seasonally wet features.
4. Walk through the site slowly (about 5 minutes to walk 100 meters), look back and
forth on either side, approximately 20 to 30 feet out. Do your best to walk in a
path such that you cover the entire site with this visual field, or at least all of the
areas of apparently suitable habitat.
5. If you leave your path to look at a particular butterfly, do your best to return to
where you left your path when you resume walking/searching through the site.
6. When a suspected Mardon skipper butterfly is encountered, we net the butterfly to
confirm its identification. This is especially important because of its similarity to
the Sonoran skipper Polites sonora, which also occurs at many sites supporting
Mardon skippers. No vouchers were taken at sites.
7. Record all data for sites whether butterflies are seen or not. In this way, we
document both new sites where P. mardon is found and, as well as our overall
search effort.
MANAGEMENT RECOMMENDATIONS
Mardon skipper populations face a variety of threats, including cattle grazing, conifer and
shrub encroachment, off road vehicle (ORV) use of meadows, recreation (including
camping), applications of Btk, and landownership patterns that may lead to incompatible
uses on adjacent land, thus affecting Mardon skipper site condition and survival. In this
report, we provide general recommendations for managing grazing, conifer
encroachment, ORV use and Btk applications. We also provide general recommendations
for how to preserve Mardon skipper populations while using fire as a management tool.
Other threats, such as shrub encroachment, recreation, and incompatible uses of nearby
lands are not addressed in this report.
Cattle Grazing
Most of the Mardon skipper sites have some grazing by cattle. Livestock grazing may
cause adverse impacts to butterfly populations by (1) trampling eggs, larvae, pupae, and
adults, (2) eating larval and adult food sources, and (3) disturbing the soil, which allows
weeds to invade (Warren 1993). Tall-grass and mixed-grass prairies appear to be very
susceptible to the effects of overgrazing (McCabe and Post 1997, Royer and Marrone
1992, Royer and Royer 1998, cited in COSEWIC 2003), “which reduced or eliminated
critical adult nectar sources and removes forage for larvae.” In a study on the Dakota
skipper (Hesperia dacotae), Dana (1997) found that grazing cattle reduced skipper
numbers in direct proportion to grazing intensity. However, grazing is not always
detrimental (Dana 1991); “light or light rotational grazing can be beneficial by creating
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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areas of mixed-grass vegetation structure preferred by the (Dakota) skipper” (Dana
1991).
In order for grazing to have a minimal impact on the Mardon skipper, the combination of
timing, intensity, and duration must be found that is best suited for the specific ecology of
the butterfly. In some sites the correct solution may be to eliminate grazing while in other
sites some grazing at the appropriate time of the year may not negatively impact the site.
In Washington, adult Mardon skippers require adequate floral nectar for survival,
successful reproduction, and adequate egg production from mid-May through early
August.2 Livestock grazing or site use during this period reduces or altogether removes
key nectar resources. Likewise, grazing when butterfly larvae are active on host plants
can result in direct mortality or remove important larval vegetation (Smallidge & Leopold
1997). In Washington, Mardon larvae are believed to be active from approximately late
March through October, although this window of activity is variable, and is probably
influenced by the elevation of each site. Grazing intensity and duration are also important
to consider. Although intensive grazing has been shown to be categorically detrimental,
moderate to light stocking levels with herds rotated through the management area to
create a mosaic pattern of grazing stages can be a useful method for halting succession
(Schtickzelle et al 2007). The timing and frequency of rotation depends on both the size
of the herd and the size of the grazed area (Schtickzelle et al 2007). Generally speaking,
grazing periods should be short, with recovery periods for the habitat relatively long.
General Recommendations (Note: Management plans should be developed for each site)
• At the most severely impacted sites cattle should be excluded from the area to
allow the habitat time to repair.
• Grazing should never be allowed during the flight period of the adult Mardon
skipper.
• Optimally, cattle should not be allowed to enter a site when Mardon skipper
larvae are active, although more research is needed to determine the impact of
cattle on Mardon skipper larvae at various times of the year.
• Keep grazing periods short, with recovery periods for the habitat relatively long.
The BLM and Forest Service should implement a grazing study by looking at different
grazing regimes. In the long-term, habitat management research should address: 1) Does
grazing degrade, maintain, or have no effect on Mardon skipper habitat quality?, 2) What
grazing regime is least harmful to Mardon skippers and their habitat?, 3) How does site
vegetation change over time with various applications of livestock grazing? For areas
where elk are present the study design should include areas that exclude cattle but not elk.
In this way we can better understand the impact of cattle grazing and work toward better
management of these sites.
2
In Washington, the Mardon skipper adult flight period varies by elevation and individual site
microclimates. Throughout the state, the flight times span from mid-May through early August, although
adult flight times at individual sites last approximately 3-4 weeks.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Prescribed fire
Due to the importance of fire in maintaining many native ecosystems, the use of
controlled burning as a management tool has become increasingly common. Although
the effects of fire on vegetation and vertebrate communities are more widely understood
than the effects of fire on invertebrates, fire can benefit, harm, or have no significant
effect on invertebrates depending on the biology of the specific taxa (Gibson et al 1992).
Burning of meadows with populations of butterflies, such as the Mardon skipper, could
extirpate the population if not done carefully, with consideration of butterfly behavior
and life stage at time of burn and knowledge of where the skipper population is
distributed across the meadow. In addition, with isolated populations, there are often no
source populations available for recolonization once a population has been locally
extirpated. Swengel (1996) and Swengel and Swengel (2001) found that fire had
consistent negative effects on prairie specialist species of butterflies that persisted for 3-5
years post-fire. In a modeling approach Schultz and Crone (1998) found that burning
one-third of the butterfly occupied habitat every year to control encroaching woody
shrubs would maximize the average annual population growth rate of Fender’s Blue
Icaricia icarioides fenderi. Swengel (1996) suggests that management techniques should
be varied between sites, providing not only short term diversity of habitat, but
counteracting any potential long term effects that reliance on one method of site
management may have on a given population of butterflies. If controlled use of fire
within a Mardon skipper occupied site is feasible, and there is a management goal that
can be best accomplished with controlled burning, then in order to protect the Mardon
skipper population, specific steps must be employed in conducting the burn. A careful
and well-researched prescribed burning regimen should have the correct combination of
timing, intensity, and size that is appropriate for the management area and will result in
long-term stability of Mardon skipper populations. Knowledge of how butterflies
respond to fire is integral to designing an effective fire management strategy. Sites that
support small numbers of individuals should in general not be considered for burns.
General Recommendations (Note: Management plans should be developed for each site)
• Conditions (site size, access, vegetation desiccation and humidity levels) must
allow for controlling fire once it starts.
• A management objective has been defined that will be best accomplished by use
of fire.
• Identify core Mardon skipper habitats, especially egg-laying areas, as part of a
burn plan.
• Burn in fall or early winter as Mardon skippers have ceased foraging and are
present as larvae, or in a state of diapause to prepare for the winter.
• A single prescribed fire should not burn more than 1/10 to 1/5 of the core habitat
in any given year.
• As a fire moves through an area it may leave small patches unburned. These skips
should be left intact as potential micro-refuges.
• Periods between managed burns at the same site should be conservative and can
be anywhere from 3-10 years for adequate recovery of butterfly populations,
depending on the ecosystem.
• Not all sites within the same complex should be burned.
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•
•
If burns are undertaken a comprehensive monitoring program should be put in
place to determine the short and long term impact on the population.
Care must be taken to avoid actions that could degrade habitat and kill individual
skippers as a result of heavy equipment use or people trampling meadows.
Encroaching conifers (Note: Management plans should be developed for each site)
In some areas fire suppression has led to grassland encroachment by native trees and
shrubs (Potter and Fleckenstein, 2001), which could have a negative impact on Mardon
populations. Many Mardon skipper meadows have encroaching conifers. At sites where
conifers are encroaching, the small trees should be removed as soon as possible, before
the trees grow larger and reproduce. Management plans may need to be developed to
selectively and carefully remove some young conifers.
General Recommendations
• Conifers over 4” Diameter at Breast Height (DBH) should be left at the site.
• Wherever possible hand cutting with chainsaws or handsaws would be optimal.
• Care must be taken to avoid actions that could degrade habitat and kill individual
skippers as a result of heavy equipment use, people trampling meadows, piling of
trees in meadows, or burning of piles in meadow habitat.
• Larger trees at the edges of meadows should be maintained since they may play
an important role in maintaining the microclimate and hydrology at the sites.
Off-road vehicles (ORVs)
When ORVs drive through meadows occupied by the Mardon skipper, the skipper is
directly threatened. In areas with ORV traffic, we recommend fencing off core Mardon
skipper habitat areas.
Use of Btk
Btk (Bacillus thuringiensis var. kurstaki), a Lepidoptera-specific insecticide, has been
widely used to treat defoliators in western forests (Wagner and Miller 1995). Btk is a
bacterium, which when ingested, is lethal to butterfly and moth larvae.
Species such as the Mardon skipper that are single-brooded with spring-active larvae that
feed during the application period for the target species are especially vulnerable to Btk
(Wagner and Miller 1995). Because of the Mardon skipper’s current patchy distribution
on isolated sites and low vagility, its populations are even more threatened by Btk
applications due to the decreased probability of re-colonization.
The threat of Btk is heightened because Btk has been shown to drift at toxic
concentrations for distances greater than two miles from target spray areas (Barry 1993
and Whaley et al. 1998). As a result, aerial spraying with Btk can have significant
adverse effects on Mardon skippers in the general area of an aerial Btk spray project. We
recommend not spraying Btk on forested areas within five miles of any Mardon skipper
population.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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SITES VISITED
1111 (1-5)
Sarina Jepsen and Logan Lauvray of the Xerces Society surveyed 5 meadows along trail
1111 on July 8, 2007 from 12:10 to 2:15 p.m. Mardon skippers were not observed at any
of these sites, but the following meadows appeared to have suitable Mardon skipper
habitat and should be checked earlier in the season next year: 1111(1), 1111(2), and
1111(3). See Appendix A for the geographic location of each site. 1111(1), 1111(2) and
1111(3) had the known larval host plants: Festuca sp. and Carex sp. They also had
patches of Danthonia unispicata, a plant that was observed in high abundance at a new
Washington Mardon skipper site with 450+ individuals (Mardon skippers use Danthonia
californica as an oviposition plant in southern Oregon). Sites 1111(4) and 1111(5) looked
less likely to support Mardon skippers, mainly because they were very dry and there were
no areas within the meadows that looked like they had surface water earlier in the season.
Figure 1. 1111(1)
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Figure 2. 1111(2)
Cash Prairie
Sarina and Logan (Xerces) surveyed Cash Prairie on July 8, 2007 from 5:45 to 6:45 p.m.
No Mardon skippers were observed at this site. This large meadow has some wet areas,
abundant floral resources, Festuca sp. and Carex sp. Cash Prairie is significantly higher
(5900-6100 feet) than the highest known Mardon sites. The plant community appeared
appropriate to support Mardon skippers, (it was moist and had appropriate host plants) so
we did not think that our timing was off in conducting this survey. Although we surveyed
late in the day the weather was appropriate for seeing Mardon on the wing. Thus, we
would not recommend resurveying this site next year.
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Figure 3. Cash Prairie
Conrad Meadows Complex (Fingers 1-2, 3-9)
Fingers 1, 2
On June 27, 2007, from 12:45 to 3:30 p.m., Sarina and Logan (Xerces), Joan St. Hilaire
of the USFS, and Jeff Bernatowitz (Bernie) and Will Moore of WDFW surveyed two
‘fingers’ of Conrad Meadows that extend east of the south fork of the Tieton River. No
Mardon skippers were observed in Conrad Finger 1; the habitat appeared too dry to
support Mardon skippers. In Conrad Finger 2, 457 Mardon skippers were observed in a
one-day count (Figures 4 and 5). The highest density of Mardon skippers was in the
southeast end of the meadow, in an area dominated by onespike oatgrass (Danthonia
unispicata). Festuca sp. and Carex sp. were also present in this meadow. On July 10,
2007, Sarina Jepsen and Logan Lauvray returned to the Conrad Finger 2 site, and
observed only 3 Mardon skippers. We counted 40 cattle grazing on this site. We noted
that there were no longer any flowering plants, and that many of the larval host plants had
been eaten or trampled (Figure 6). Please see the above recommendations that we provide
regarding cattle grazing and butterfly habitat conservation.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 4. Conrad Finger 2 on June 27, 2007
Figure 5. Conrad Finger 2 on June 27, 2007
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Figure 6. Cattle grazing on Conrad Finger 2 on 7/10/2007
Conrad 3
Bernie and Will (WDFW) and Sarina (Xerces) surveyed Conrad 3 meadow along the trail
just west of Conrad Meadows on June 27, 2007 at 4:00 p.m. Four Mardon skippers were
observed in this small meadow (approximately 0.25 acres). No Festuca sp. was observed,
but there was abundant Danthonia unispicata. There was no surface water present in this
meadow.
Conrad 4
Joan (USFS), Will and Bernie (WDFW), and Logan and Sarina (Xerces) surveyed
Conrad 4, a small meadow near the bridge that crosses the south fork of the Tieton River.
No Mardon skippers were observed at this site. The area marked on the map (provided by
USFS) as a meadow was filled with alders and small conifers. The meadow surveyed was
the closest meadow to this mapped area but did not seem appropriate to support Mardon
skippers.
Conrad 5
Sarina and Logan (Xerces), Joan (USFS), and Bernie and Will (WDFW) surveyed a
small meadow: ‘Conrad 5’ on June 27, 2007 at 5:05 p.m. This meadow is just northwest
of the bridge that crosses the S. fork of the Tieton River. This meadow is a small opening
in the trees, on both sides of a dirt road. No Mardon skippers were observed at this site,
and the plant community did not seem appropriate to support Mardon skippers. While
there was abundant Carex sp., no Festuca sp. or Danthonia sp. was observed.
Conrad 6
Sarina and Logan (Xerces) surveyed a large meadow complex along trail 1120 on June
27, 2007 at 5:40 p.m. Twenty-four Mardon skippers were observed in this meadow. Part
of the meadow was in the shade during the time that it was surveyed; it was perhaps too
late in the day to get an accurate one-day count of this site. Thus, this meadow should be
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resurveyed next year. This site has a large amount of Danthonia unispicata and Carex
sp. One female Mardon skipper was observed ovipositing on Carex sp. This meadow has
a shed and some old tractors sitting in it.
Threats: This meadow has many encroaching small pines and a fair amount of cattle
activity.
Figure 7. Conrad 6
Figure 8. Conrad 6
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Conrad 7
Sarina and Logan (Xerces) visited ‘Conrad 7’ meadow along trail 1120 at the sign for the
Goat Rocks Wilderness. The meadow was visited at 6:36 p.m. on July 7, 2007. It was
entirely shaded, so it was not surveyed for Mardon skippers. The habitat looked like it
could potentially support Mardon skippers, so it should be surveyed next year. This site
had abundant Carex sp., although no Festuca sp. was observed.
Figure 9. Conrad 7
Conrad 8
Logan and Sarina (Xerces) visited ‘Conrad 8’ meadow along trail 1120 at 6:25 p.m. on
July 7, 2007. This meadow was not surveyed because it was entirely in the shade. The
meadow ground was very wet in most places, with a small amount of drier ground near
the trail edge. It appeared to be too wet to support Mardon skippers, and thus we place a
low priority on resurveying it in future years.
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Figure 10. Conrad 8
Conrad 9
Sarina and Logan (Xerces) visited this meadow on July 10, 2007 at 7:10 p.m. This
meadow is just east of the area where the Conrad Creek joins the South Fork of the
Tieton River. The meadow was entirely shaded, so it was not surveyed for Mardon
skippers. However, the habitat was assessed for its suitability to support Mardon
skippers. This meadow is almost entirely a wetland, filled with Bog orchids, Carex spp.,
Castilleja sp., and grasses. It appears to be too wet to support Mardon skippers, and thus
we do not recommend resurveying this meadow in future years.
Deadhorse Meadow
Sarina and Logan (Xerces) surveyed this meadow on July 8, 2007 at 11:30 a.m. This
meadow consisted of a very small opening in the trees (~1 acre) at the end of Rd.
1382000. There were no Mardon skippers and there was no suitable Mardon skipper
habitat. This meadow appears to have once been a forest that has been logged.
Four Way Meadow
Sarina and Logan (Xerces) surveyed a narrow meadow that runs across Highway 19
(Four Way Meadow) on July 9, 2007 at 5:45 p.m. No Mardon skippers were observed,
although the habitat looked like it could support Mardon skippers. This site should be
checked much earlier next year. The elevation is low (3174 feet), so one would expect
that if Mardon skippers were here, they would be active about one month previous to the
time that this meadow was checked (it should be revisited in early June). This site is also
much farther north than any of the other known Mardon skipper sites. Many flowering
forbs, Festuca sp., Carex sp. and Danthonia unispicata were all present at this site.
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Figure 11. Four Way Meadow
Fox Meadow
Sarina and Logan (Xerces) surveyed this meadow on July 8, 2007 at 2:50 p.m. No
Mardon skippers were observed, although parts of this meadow appeared to be suitable to
support Mardon skippers. Part of this meadow is in wetland habitat; the upland, drier
areas contained flowering forbs, Festuca sp., Carex sp., and some Danthonia unispicata.
The upland areas were surveyed intensively for Mardon skippers. This site is somewhat
higher than any of the known Mardon skipper sites in Washington (5717 feet). We
believe that we surveyed this meadow at the most appropriate time of year, given its
elevation. Thus, we would not recommend resurveying it next year.
Lost Meadow
Sarina and Logan (Xerces) visited this meadow on July 9, 2007 at 6:40 p.m. No Mardon
skippers were observed, although the habitat looked like it could potentially support
Mardon skippers. Lost Meadow had Festuca sp., Potentilla sp., many flowering forbs and
a small, seasonal creek ran through the meadow. This meadow sits at 3115 feet; one
would expect Mardon skippers to be active at a site of this elevation in early June, rather
than when it was surveyed in early July. For these reasons, we would recommend
rechecking Lost Meadow earlier in the season next year. This meadow is also farther
north than any of the known Mardon skipper sites.
Mad Cow Meadow
Sarina and Logan (Xerces) surveyed part of this meadow on July 8, 2007 at 7:15 p.m. No
Mardon skippers were observed in this small, wet meadow. The habitat, which included
some Festuca sp. and Carex sp., looked like it could potentially support Mardon skippers.
However, all of the flowers (including Potentilla sp.) had been eaten off of their stalks,
presumably by cattle. This meadow was not completely surveyed because part of it was
in the shade and an aggressive cow was present. We recommend rechecking this meadow
again next year.
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Figure 12. Mad Cow meadow
Minnie Meadows
Sarina and Logan (Xerces) surveyed Minnie Meadows at 10:30 a.m. on July 7, 2007. No
Mardon skippers were observed. Vince Harke and Joan St. Hilaire found 38 Mardon
skippers on June 20, 2007. Their data sheet indicated that there was a higher density of
Mardon skippers within a research exclosure than outside of it (Figure 13), which
appeared to be due to the higher abundance and diversity of flowering plants inside of the
exclosure. This site and cattle exclosure could potentially be incorporated into a future
study that examines the effects of grazing on the Mardon skipper.
Figure 13. Minnie meadows cattle exclosure; note the higher abundance of
flowering plants within the exclosure (right) than outside of the exclosure (left)
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Mosquito Valley 1-3
Sarina and Logan (Xerces) surveyed two meadows along trail 1106 and one meadow
along trail 1156 near Mosquito Valley on July 8, 2007. No Mardon skippers were
observed at any of the three meadows surveyed. Mosquito Valley 1 and 2 (along trail
1106) were very wet meadows, with wetlands interspersed throughout them. The ground
of both meadows seemed too wet to support Mardon skippers. The habitat at Mosquito
Valley 3 (a large meadow complex in Lewis County, just past Dumbell lake along trail
1156) appeared to be more suitable for Mardon skippers; there was a small creek running
through the meadow, and Festuca sp., Carex sp. and many flowering plants were present.
While the habitat looked promising, we surveyed the site extensively and did not find any
Mardon skippers. We believe we visited the site at the appropriate time of day and time
of year to see Mardon on the wing, so we would not recommend resurveying this site.
Figure 14. Mosquito Valley 3
Pinegrass 1 and 2
Sarina and Logan (Xerces), Joan (USFS), and Bernie and Will (WDFW) surveyed two
meadows in the Pinegrass area on July 6, 2007 from 12:35 to 1:55 p.m. At Pinegrass 1,
approximately 21 Mardon skippers were counted (32 total skippers were observed, about
2/3 of which were Mardon skippers and 1/3 were Sonora skippers. We positively
identified 20% of the skippers that we counted). Two Mardon skippers were counted at
Pinegrass 2. The plant community at Pinegrass 1 contains Festuca sp., Carex sp., clover,
grasses, and false hellebore. This meadow appeared very dry, but it looks like it may have
been wet earlier in the season. Pinegrass 2 is a mostly dry meadow off of Road 741 that
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
18
appeared to be wet earlier in the season. We recommend surveying this meadow 2-3
weeks earlier next season, as we think it is possible that we observed the tail end of the
Mardon skipper emergence.
Threats: Many small fir trees are encroaching on this meadow.
Figure 15. Pinegrass 1
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 16. Pinegrass 2
Rimrock Lake South
Sarina and Logan (Xerces), Joan (USFS), and Bernie and Will (WDFW) surveyed
Rimrock Lake South on July 6, 2007 at 11:55 a.m. There were no Mardon skippers
observed, and the habitat did not look like it would support Mardon skippers. There was
no Festuca sp., although some Carex sp. was present. We do not recommend surveying
this site in future years.
Surprise Lake Complex
A series of meadows were surveyed along trail 1120. All meadows along trail 1120 that
are between Conrad meadows and the location where Conrad Creek flows into the south
fork of the Tieton River are labeled Conrad 3-9; all meadows along trail 1120 that are
east of the joining of the two creeks are labeled Surprise Lake 1-11. Surprise Lake
Meadows 1-4 are before the beginning of the ‘loop’ trail that goes to Surprise Lake;
Surprise Lake Meadows 5-11 are within the ‘loop’ trail. Appendix A lists the geographic
location of each site and site maps are included in Appendix C.
Surprise Lake 1
Sarina and Logan (Xerces) surveyed Surprise Lake 1 on July 7, 2007 at 2:40 p.m.
Twenty-five Mardon skippers were observed at this site. The Mardon skippers were
mainly found in the drier, upland area of this meadow that abuts trail 1120. This meadow
contains abundant Festuca sp., Carex sp., false hellebore, wild strawberry, Calochortus
sp., yarrow, clover, vetch, dandelion, penstemon, wild carrot, potentilla and other grasses.
Threats: There is some conifer encroachment on this meadow. Also, there is a fair
amount of grazing on this meadow.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 17. Surprise Lake 1
Surprise Lake 2
Sarina and Logan (Xerces) surveyed Surprise Lake 2 on July 7, 2007 at 3:40 p.m. No
Mardon skippers were observed. This is a long wetland/ wet meadow complex on the
south side of the south fork of the Tieton River. This site has very little mesic habitat and
does not look like it would support Mardon skippers. We do not recommend resurveying
this meadow in the future.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 18. Surprise Lake 2
Surprise Lake 3
Sarina and Logan (Xerces) surveyed this meadow on July 7, 2007 at 4:15 p.m. No
Mardon skippers were observed, although 6 Sonora skippers were observed and the
habitat looked like it could support Mardon skippers. We observed many flowering forbs,
Festuca sp., Carex sp. and Danthonia unispicata. We recommend resurveying this site in
the future.
Figure 19. Surprise Lake 3
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Surprise Lake 4
Sarina and Logan (Xerces) surveyed Surprise Lake 4 on July 7, 2007. No Mardon
skippers were observed, and there was no Festuca sp. observed. The habitat looked
somewhat dry on the edges, although there was a wet area in the middle of the meadow.
We recommend placing a medium priority on resurveying this site in the future.
Surprise Lake 5
Sarina and Logan (Xerces) surveyed a complex of four interconnected meadows just east
of the beginning of the ‘loop’ portion of the Surprise Lake loop trail (1120) at 5:20 p.m.
on July 7, 2007. No Mardon skippers were observed. The habitat did not look like it
would support Mardon skippers, as no Festuca sp. was observed and the meadows were
relatively dry. We would not place a high priority on resurveying these sites.
Surprise Lake 6
Sarina and Logan (Xerces) surveyed Surprise Lake 6 on July 10, 2007 at 1:10 p.m.,
which was a large complex of meadows along approximately 0.5 miles of trail 1120, just
west of Surprise Lake. No Mardon skippers were observed at any of these meadows.
Many of these meadows have small, glacier fed creeks running through them. The plant
community looks very different from the plant community at the lower elevation known
Mardon skipper sites. We do not recommend resurveying any of these sites.
Figure 20. Surprise Lake 6
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Surprise Lake 7
Sarina and Logan (Xerces) surveyed Surprise Lake 7 at 3:00 p.m. on July 10, 2007. No
Mardon skippers were observed, and the habitat does not look ideal. This meadow is
filled with false hellebore, cow parsnip, yarrow, and grasses. We do not recommend
resurveying this meadow in the future.
Figure 21. Surprise Lake 7
Surprise Lake 8
Sarina and Logan (Xerces) surveyed Surprise Lake 8 on July 10, 2007 at 3:25 p.m. Two
Mardon skippers were observed and photographed. Four unidentified skippers were also
observed, but they were not counted since their identity could not be confirmed. The 2
Mardon skippers from this site were concentrated around the tiny, mossy creek that
emerges from the ground and flows through this site (Figure 22). This site is the highest
known Mardon skipper site in Washington (5237 feet). There is some Festuca sp. and
abundant Carex sp. in this meadow. There is also false hellebore, lupine, cow parsnip,
and other grasses and forbs. This meadow is on both sides of trail 1120, but the Mardon
skippers were only observed in the part of the meadow that is on the north side of the
trail.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 22. Surprise Lake 8
Figure 23. Surprise Lake 8
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Surprise Lake 9
Sarina and Logan (Xerces) surveyed Surprise Lake 9 on July 10, 2007 from 4:05 to 5:15
p.m. One hundred and fifty-three Mardon skippers were observed in a one-day count of
this site. Most of the Mardon skippers were nectaring on the abundant vetch or the
Calochortus sp., although one was observed nectaring on lupine. Festuca sp. was not
observed at this site, although abundant Carex sp. was observed. This is a damp,
southeast sloping meadow of approximately 7 acres with a small, mossy creek running
through the middle of it. Some of the other plants observed at this site include: cow
parsnip, false hellebore, grasses, blue-eyed iris, yarrow, and clover.
Threats: Many small conifers are encroaching on this meadow.
Figure 24. Surprise Lake 9
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 25. Surprise Lake 9
Surprise Lake 10
Sarina and Logan (Xerces) surveyed Surprise Lake 10 on July 10, 2007 at 5:25 p.m.
Eight Mardon skippers were observed. Surprise Lake 10 consists of two interconnected
meadows (totaling about 5 acres) that are predominately on the south side of trail 1120.
This meadow was not fully surveyed because most of it was in the shade. Thus, it should
be resurveyed next year for a more accurate assessment of the actual Mardon skipper
population size. At this site we observed Festuca sp, vetch, Calochortus sp., lupines,
phlox, grasses, penstemon and false hellebore.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 26. Surprise Lake 10
Surprise Lake 11
Sarina and Logan (Xerces) surveyed Surprise Lake 11, a small meadow just south of trail
1120, on July 10, 2007 at 5:45 p.m. Sixteen Mardon skippers were observed in this south
sloping meadow. There was a fair amount of moss present on the ground, although this
site is somewhat drier than Surprise Lake 9 and 10. Some of the plants in this meadow
include: vetch, yarrow, lupine, Calochortus sp., and Carex sp.
Figure 27. Surprise Lake 11
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Wildcat 1-3
Wildcat 1
Sarina and Logan (Xerces), Joan (USFS), and Bernie and Will (WDFW) surveyed
Wildcat 1 on July 6, 2007 from 2:40 to 3:05 p.m. Two Mardon skippers were observed at
this site. This meadow is approximately 10 acres, and is along Wildcat Road (1306).
There is a seasonal creek that runs through the meadow that is mostly dry, but still has a
few pockets of water. The area where the skippers were found is just SE of Wildcat Road.
The habitat looked like it was beginning to dry out. This site should be checked
approximately 2 weeks earlier in the season next year to get a more accurate estimate of
the Mardon skipper population size.
Figure 28. Wildcat 1
Wildcat 2
Sarina and Logan (Xerces), Joan (USFS), and Bernie and Will (WDFW) surveyed
Wildcat 2 on July 6, 2007 from 4:15 to 4:40 p.m. No Mardon skippers were observed at
this site. However, two unusual skippers were netted and photographed (Figures 30 and
31). Those of us in the field were unable to conclusively determine whether these
skippers were Polites mardon, Polites sonora, or another Polites species. The
photographs were shared with many lepidopterists and others who have worked with
Mardon skippers. Some individuals concluded that that they were Polites mardon,
whereas others concluded that they were Polites sonora. The three lepidopterists: Andy
Warren, John Pelham, and Robert Michael Pyle, all independently concluded that the
individuals were Polites sonora. Andy Warren noted that they were aberrant individuals.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
29
This site should be revisited next year, and, if similar skippers are encountered, at least
one male specimen should be collected and sent to either John Pelham or Andy Warren.
This finding presents somewhat of a problem for field surveys, as the aberrant P. sonora
specimens had ventral hind wing markings that somewhat mimick those of P. mardon
(elongated, rectangular shaped cells). The ventral hindwing character is the primary
character that is used in field surveys for P. mardon. This experience illustrates the need
to collect a voucher male specimen at any sites where identification of a specimen is
disputed. It also will be important for surveyors to identify male specimens using the
stigma on the dorsal forewing.
Figure 29. Wildcat 2
Figure 30. This butterfly from Wildcat 2 was identified as
Polites sonora by Andy Warren, John Pelham, and Robert Michael Pyle
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 31. This butterfly from Wildcat 2 was identified as Polites
sonora by Andy Warren, John Pelham, and Robert Michael Pyle
Wildcat 3
Sarina and Logan (Xerces) surveyed a third meadow, Wildcat 3, along Wildcat Road at
5:25 p.m. on July 6, 2007. No Mardon skippers were observed, although the habitat
looked like it could support Mardon skippers. It should be checked earlier in the season
next year. There are a few small streams and small pools of water within this site.
Abundant Festuca sp. was observed.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Figure 32. Wildcat 3
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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LITERATURE CITED
Barry JW. 1993. Predicting and measuring drift of Bacillus thuringiensis sprays.
Environmental Toxicology and Chemistry. 12:1977-1989.
Beyer L and SH Black. 2007. Site Utilization by Adults and Larvae of Mardon Skipper
Butterfly (Polites mardon) at four sites in Washington and Oregon. Final Report to the
Forest Service and BLM from the Xerces Society.
Black SH and M Vaughan. 2005. Species Profile: Polites mardon. In Shepherd, M.D.,
D.M. Vaughan, and S.H. Black (Eds). Red List of Pollinator Insects of North America.
CD-ROM Version 1 (May 2005). Portland, OR: The Xerces Society for Invertebrate
Conservation.
COSEWIC 2003. COSEWIC Assessment and Status Report on the Dakota Skipper,
Hesperia dacotae, in Canada. Committee on the Status of Endangered Wildlife in
Canada. Ottawa. vii + 35 pp. (www.sararegistry.gc.ca/status/status_e.cfm).
Dana RP. 1991. Conservation management of the prairie skippers, Hesperia dacotae and
Hesperia ottoe: basic biology and threat of mortality during prescribed burning in spring.
Minnesota Agricultural Experiment Station Bulletin 594-1991 (AD-SB-5511-S).
University of Minnesota, St. Paul. 63 pp.
Dana R. 1997. Characterization of three Dakota skipper sites in Minnesota, a report
prepared for the U. S. Fish and Wildlife Service. Minnesota Department of Natural
Resources.
Gibson CD, Brown VK, Losito L, and McGavin GC. 1992. The Response of Invertebrate
Assemblies to Grazing. Ecography 15(2): 166-76.
Mattoon SO, JF Emmel and TC Emmel. 1998. The Distribution of Polites mardon
(Lepidoptera: Hesperiidae) in North America, and Description of a New Subspecies from
Southern Oregon. Systematics of Western North American Butterflies.
Pyle RM. 2002. The Butterflies of Cascadia. Seattle Audubon Society. Seattle, WA.
Potter A and J Fleckenstein. 2001. Southern Cascade Surveys for the Mardon Skipper,
Summary Year 2000. Washington Department of Fish and Wildlife. Olympia, WA. 11pp.
Runquist E. 2004. Unpublished Report and presentation. Workshop on the ecology and
status of the mardon skipper (Polites mardon) An unusual Pacific Northwest butterfly.
Ashland, Oregon.
Schtickzelle N, C Turlure and M Baguette. 2007. Grazing management impacts on the
viability of the threatened bog fritillary butterfly Proclossiana eunomia. Biological
Conservation, 136(4): 651-660.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
33
Schultz CB and EE Crone. 1998. Burning Prairie to Restore Butterfly Habitat: A
Modeling Approach to Management Tradeoffs for the Fender's Blue. Restoration
Ecology, 6(3): 244-252.
Smallidge PJ and DJ Leopold. 1997. Vegetation management for the maintenance and
conservation of butterfly habitats in temperate human-dominated habitats. Landscape
and Urban Planning 38: 259-280.
Swengel AB and SR Swengel. 2001. Effects of prairie and barrens management on
butterfly faunal composition. Biodiversity and Conservation, 10(10): 1757-1785.
Swengel AB. 1996. Effects of fire and hay management on abundance of prairie
butterflies. Biological Conservation 76: 73–85.
Wagner D and JC Miller. 1995. Must butterflies die for the gypsy moth’s sins? American
Butterflies. 3(3):19-23.
Warren MS. 1993. A review of butterfly conservation in central southern Britain: II. Site
management and habitat selection of key species. Biological Conservation. 64:37-49.
Warren AD. 2005. Lepidoptera of North America 6. Butterflies of Oregon – Their
Taxonomy Distribution and Biology. Corvallis OR.
Whaley WH, J Arnold and BG Schaaleje. 1998. Canyon drift and dispersion of Bacillus
thuringiensis and its effects on selected nontarget lepidpoterans in Utah. Environmental
Entomology. 27(3)539-548.
ACKNOWLEDGEMENTS
Thanks to Joan St. Hilaire of The U.S. Forest Service for providing maps and helping
with surveys. Jodi Leingang of The U.S. Forest Service provided botanical expertise for
this project. Thank you also to Bernie (Jeff Bernatowitz) and Will Moore of the
Washington Department of Fish and Wildlife for their help with surveying on two days.
Many thanks to Ann Potter, who reviewed the management recommendations and
provided taxonomic expertise. Dana Ross, John Pelham, Robert M. Pyle and Andy
Warren also provided taxonomic expertise with photographs of problem specimens.
Cheryl Schultz and Loni Beyer also reviewed the management recommendations.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Appendix A: Summary of all sites and areas surveyed in Washington by the Xerces
Society (Sarina Jepsen and Logan Lauvray) during the 2007 field season.
Site
1111(1)
1111(2)
1111(3)
1111(4)
1111(5)
Cash Prairie
Conrad Finger 1
Conrad Finger 2
Conrad 3
Conrad 4
Conrad 5
Conrad 6
Conrad 7
Conrad 8
Conrad 9
Deadhorse Meadow
Four Way
Fox Meadow
Lost Meadow
Mad Cow Meadow
Minnie Meadows
Mosquito Valley 1
Mosquito Valley 2
Mosquito Valley 3
Pinegrass 1
Pinegrass 2
Rimrock Lake South
Surprise Lake 1
Surprise Lake 2
Surprise Lake 3
Surprise Lake 4
Surprise Lake 5
Surprise Lake 6
Surprise Lake 7
Surprise Lake 8
Surprise Lake 9
Surprise Lake 10
Surprise Lake 11
Wildcat 1
Wildcat 2
Elevation
(feet)
4682
4896
5050
5284
5430
6000
4269
4052
4138
4078
4123
4147
4143
4188
4150
4300
3174
5717
3115
3649
3527
3658
5058
5120
4044
4217
3022
4181
4216
4254
4272
4326
5320
5342
5237
5048
5001
5069
3704
4677
Mardon Resurvey
extant
in 2008
N
Y
N
Y
N
Y
N
N
N
N
N
N
N
N
Y
Y
Y
Y
N
N
N
N
Y
Y
N
Y
N
N
N
N
N
N
N
Y
N
N
N
Y
N
Y
Y*
Y
N
N
N
N
N
N
Y
Y
Y
Y
N
N
Y
Y
N
N
N
Y
N
Y
N
N
N
N
N
N
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
N
Y
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
35
Wildcat 3
3827
N
Y
*38 Mardon skippers were observed at Minnie Meadows by Vince Harke and Joan St. Hilaire on June 20,
2007, but no Mardon skippers were observed by Sarina Jepsen and Logan Lauvray on July 7, 2007.
Appendix B: Summary of new Mardon skipper sites in Washington after the 2007 field
season, approximate meadow size, and recorded one day counts from these sites.
Site Name
Conrad Meadows Complex
Conrad Finger 2
Conrad 3
Conrad 6
Minnie Meadows site
Minnie Meadows
Pinegrass Complex
Pinegrass 1
Pinegrass 2
Surprise Lake Complex
Surprise Lake 1
Surprise Lake 8
Surprise Lake 9
Surprise Lake 10
Surprise Lake 11
Wildcat site
Wildcat 1
Approximate
meadow size
Date
Surveyed
Day
Count
10 acres
0.25 acres
6 acres
6/27/2007
6/27/2007
6/27/2007
457
4
24
10 acres
6/20/2007*
38
4 acres
6 acres
7/6/2007
7/6/2007
32
2
10 acres
2 acres
7 acres
5 acres
1 acre
7/7/2007
7/10/2007
7/10/2007
7/10/2007
7/10/2007
25
2
153
8
16
10 acres
7/6/2007
2
*Vince Harke and Joan St. Hilaire conducted the survey on 6/20/07 at Minnie Meadows and observed 38
Mardon skippers. Sarina Jepsen and Logan Lauvray conducted a second survey on 7/7/07, but did not
observe any Mardon skippers at that time.
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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Appendix C: Maps of all sites visited. Note: sites outlined in red indicate extant Mardon
skipper populations. Sites outlined in blue indicate no Mardon skippers were observed
and the site should not be rechecked in future years. Sites outlined in green indicate
Mardon skippers were not observed, but the site should be rechecked in the future.
*Please contact the Xerces Society for a complete version of this report (including
all maps): Tel. 503-232-6639, sarina@xerces.org
Report: Xerces Society Surveys for Polites mardon in Washington (Summer 2007)
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